Ethernet: The Backbone of Modern Networking

Introduction

• Ethernet was developed at Xerox PARC between 1973 and 1974.
• It was first standardized in 1983 as IEEE 802.3

Why Ethernet?

• To provide an Internet connection and connect devices to LAN (Local Area Network).
• Cost-effective.

Exploring IEEE 802.3 Ethernet Standards:

• IEEE 802 is for LAN technologies.
• 802.3i can transmit 10 Mbps.
• 802.3u can transmit 100 Mbps.
• 802.3ab can transmit 1 Gbps.
• 802.3an can transmit 10 Gbps.

Where 802.3an = 10 GBASE-T

• G - Gigabit per second.
• BASE —Baseband signaling.
• T — UTP (Unshielded Twisted Pair).

Why are the cables twisted?

• When an electric current flows through a wire, it creates a magnetic field around it (Electromagnetic induction).

• Twisting pairs of wires reduces electromagnetic interference (EMI)

• If the cable is twisted, crosstalk is reduced

Ethernet cabling standards

CAT 5 (category 5)

• Speed: 100 Mbps
• Bandwidth: 100 MHZ
• Distance: 100 m

CAT 5e (category 5 enhanced)

• Speed: 1 Gbps
• Bandwidth: 100- 250 MHz
• Distance: 100 m

CAT 6 (category 6)

• Speed: 10 Gbps
• Bandwidth: 250 MHz
• Distance: 37–55 m

CAT 6a (category 6 augmented)

• Speed: 10 Gbps
• Bandwidth: 500 MHz
• Distance: 100 m

CAT 7(category 7)

• Speed: 10 Gbps
• Bandwidth: 600 MHz
• Distance: 100 m

CAT 8.1(category 8.1)

• Speed: 25 Gbps
• Bandwidth: 2000 MHz
• Distance: 30 m

CAT 8.2(category 8.2)

• Speed: 40 Gbps
• Bandwidth: 2000 MHz
• Distance: 30 m

RJ45:

• RJ45 — Registered Jack-45
• RJ45 connectors are used to terminate the ends of Ethernet cables, allowing them to be plugged into network interfaces such as computers, switches, and routers.

Straight-through:

The wiring pinouts are identical on both ends of the cable.

Crossover:

The wiring pinouts on one end are reversed (swapped) compared to the other end.

Auto MDI-X:

• Auto Medium-Dependent Interface Crossover
• It automatically determines and adapts whether the connection cable is straight-through or crossover.

References:

1. IEEE standard for Ethernet: 802.3–2018 — IEEE Standard for Ethernet | IEEE Standard | IEEE Xplore
2. Ethernet cabling standards: Cat5, Cat6, Cat7 vs. Cat8: Which Cable is Right For You? (longrangesignal.com)